Signal lamp to indicate printing lamp condition



p 15, 1964 TATSUO AIZAWA 3,149,261

SIGNAL LAMP TO INDICATE PRINTING LAMP CONDITION Filed Aug. 8, 1960INVENTOR TATSUO AIZAWA ATTORNEY United States Patent 3,149,261 SEGNALLAIVIP TO INDICATE PRINTING LAMP CONDITION Tatsuo Aizawa,Miyabayashi-cho, Hlgashr-lru, Osaka, Japan Filed Aug. 8, 1960, Ser. No.48,165 2 Claims. (Cl. 315-435) This invention relates to an electroniccircuit for indicating or signalling when an associated circuit hasreached operating condition. More particularly, this invention relatesto a device for providing a visual signal when a sensitized materialprinting machine has reached condition for printing.

Heretofore, sensitized material printing machines have been providedhaving illuminating lamps, such as mer cury vapor lamps, for printingsensitive paper. In order to produce clear printed copy, it is necessarythat the mercury vapor lamp be heated until the light emitted therefromis of sufiicient intensity to print the sensitive paper. If sensitivepaper is passed through the machine prematurely, that is, before themercury vapor lamp is sufliciently bright, the paper is wasted andillegible or faint copy is obtained.

It has been proposed that the operator of the machine visually observethe mercury vapor lamp and judge its brightness. However, it isdifiicult to make such a judgment or estimate and wasted paper, Wastedtime and effort result. It has also been proposed to employ a voltmeterbut this is inconvenient and requires reading a dial and the instructionof personnel in reading the dial.

It is an object of the present invention to overcome the foregoingdifiiculties and disadvantages by providing an electronic circuit forvisually signalling when the mercury vapor lamp has reached sufiicientbrightness for producing clear printing.

A further object of the invention is to provide an electronic circuitfor signalling when an associated circuit has reached a predeterminedvoltage.

The invention also provides an electronic circuit including a gaseousindicating tube which glows when a parallel circuit has a predeterminedvoltage.

For a better understanding of the invention and its other objects,advantages and details, reference is now made to the present preferredembodiment of the invention which is shown, for purposes of illustrationonly, in the electrical schematic diagram of the accompanying drawing.The circuit illustrated in the drawing includes a leakage transformerand capacitor in the power source for the mercury vapor lamp. Othercircuits can be employed as the power source. Among the other circuitsare: (1) a circuit including a transformer and a reactance; (2) acircuit including a transformer, a reactance and a capacitor, (3) acircuit using only the leakage transformer; and the like.

Briefly stated, the invention includes a gaseous indicator tubeconnected in parallel with a printing mercury vapor lamp. Resistancesare connected so that the voltage at which the indicator tube glows isin a fixed and prede termined ratio to the critical voltage across themercury vapor lamp producing sufficient brightness for satisfactoryprinting. Electrical power is supplied to the circuit from a powersource through a transformer.

Referring to the drawing, a mercury vapor lamp 1 ice is mounted in asensitized material printing machine (not shown) for printing sensitivepaper. The lamp 1 supplies the illumination for the printing. The lamp 1must be heated until the voltage thereacross, V reaches a critical valueat which the lamp emits light of sufiicient brightness or intensity toprint clear copies on the sensitive paper.

A gaseous indicator or signal tube 2, which can be a neon-filledelectrical discharge tube, is connected in parallel with resistor 4.Another resistor 6 is connected in series with the parallel array ofindicator tube 2 and resistor The series combination .of resistors 4 and6 is connected in parallel with lamp 1.

Electrical power is supplied to the tube 2 and lamp 1 by a leakagetransformer 8 including a primary winding 19 supplied with power acrossthe terminals 12 and 14, a core 16, a leakage path 18, and a secondarywinding 29. One end 21 of secondary winding 20 is connected to oneterminal of condenser or capacitor 22. The opposite terminal ofcondenser 22 is connected to the parallel array of resistor 4, indicatortube 2, and mercury vapor lamp 1. The opposite end 24 of secondarywinding 20 is connected to the resistor 6 and lamp 1.

Because of the parallel relationship, the voltage across the mercuryvapor lamp 1, V equals the sum of the voltage across the resistor 6, Vplus the voltage across the resistor 4, V That is, V =V +V Also, thevoltage drop across the indicator tube 2 equals the voltage acrossresistor 4, V Thus, the voltage drop across the indicator tube 2, V isin a fixed ratio or proportion to the voltage across the lamp V Theresistor 6 serves to prevent short circuit through tube 2 when tube 2fires. Further, the resistor 6 reduces the rating of tube 2 required forindicating when the lamp 1 has reached critical voltage. That is, thetube 2 has a firing voltage below the critical voltage of lamp 1. Thecritical voltage is that voltage which just produces sufiicient lightintensity of lamp 1 required for clear printing. Thus, smaller tube 2can be employed, with greater longevity and less expense. The tube 2 isselected with a firing voltage, V 1, such that V plus V equals thecritical voltage of lamp 1.

The operation of the illustrated embodiment of the invention will now bedescribed. Power is supplied across the terminals 12 and 14 to energizethe primary winding 10 and produce an induced voltage in secondarywinding 29. Leakage path 18 maintains a steady voltage in winding 2% bysmoothing out surges of voltage in primary winding 19.

The voltage across the lamp 1 increases until the critical voltage isreached. Then the lamp 1 emits light of sufficient intensity to printclearly. When lamp 1 reaches the critical voltage, the indicator tube 2reaches its firing voltage and fires with resultant visible glowing ofthe tube. The operator observes the glowing and then commences printing.

Thus, it will be seen that the invention provides an electronicindicator circuit for efiiciently and accurately signalling when amercury vapor lamp has reached printing brightness.

While a present preferred embodiment of the invention has beenillustrated and described, it will be recognized that the invention canbe otherwise variously embodied and practiced within the scope of thefollowing claims.

3 I claim: 1. A machine for printing on sensitized material including acircuit comprising an electrical discharge lamp that emits a printinglight when at least a critical voltage is applied to said lamp; a firstresistor and a second resistor connected in series with each other, thecombination of said first and second resistors being connected inparallel with said lamp; a gaseous glow tube connected in parallel withsaid first resistor, said tube glowing when a firing voltage is appliedthereto; means continuously applying to said circuit a voltage thatrises to said critical voltage, said means being connected across saidlamp, the characteristics of said printing lamp, said resistors, andsaid glow tube being so selected and proportioned that when the glowtube fires and is lit, the lamp will be emitting a printing light.

2. A machine for printing on sensitized material including a circuitcomprising an electrical discharge lamp that emits a printing light whenat least a critical voltage is applied to. said lamp; a first resistorand a second resistor connected in serieswith each other, thecombination of said first and second resistors being connected inparallel with said lamp; a gaseous glow tube connected in parallel withsaid first resistor, said tube glowing when a firing voltage is appliedthereto; a capacitor having one terminal thereof connected to one end ofsaid lamp, a transformer including a primary winding and a secondarywinding, said secondary winding having one end thereof connected to theother terminal of said capacitor, said secondary winding having itsother end connected to the other end of said lamp; means continuouslyapplying electrical power to said prinmary winding so that a voltage isinduced in said secondary winding and the voltage across said lamp risesto said critical voltage, the characteristics of the aforementionedelements of the circuit being so selected and proportioned that when theglow tube fires and is lit, the lamp will be emitting a printing light.

References Cited in the file of this patent UNITED STATESv PATENTS2,076,278 Ryde Apr. 6, 1937 2,346,621 Sola Apr. 11, 1944 2,873,409 MostFeb. 10, 1959 2,899,606 Hicks Aug. 11, 1959

1. A MACHINE FOR PRINTING ON SENSITIZED MATERIAL INCLUDING A CIRCUIT COMPRISING AN ELECTRICAL DISCHARGE LAMP THAT EMITS A PRINTING LIGHT WHEN AT LEAST A CRITICAL VOLTAGE IS APPLIED TO SAID LAMP; A FIRST RESISTOR AND A SECOND RESISTOR CONNECTED IN SERIES WITH EACH OTHER, THE COMBINATION OF SAID FIRST AND SECOND RESISTORS BEING CONNECTED IN PARALLEL WITH SAID LAMP; A GASEOUS GLOW TUBE CONNECTED IN PARALLEL WITH SAID FIRST RESISTOR, SAID TUBE GLOWING WHEN A FIRING VOLTAGE IS APPLIED THERETO; MEANS CONTINUOUSLY APPLYING TO SAID CIRCUIT A VOLTAGE THAT RISES TO SAID CRITICAL VOLTAGE, SAID MEANS BEING CONNECTED ACROSS SAID LAMP, THE CHARACTERISTICS OF SAID PRINTING LAMP, SAID RESISTORS, AND SAID GLOW TUBE BEING SO SELECTED AND PROPORTIONED THAT WHEN THE GLOW TUBE FIRES AND IS LIT, THE LAMP WILL BE EMITTING A PRINTING LIGHT. 